It is well known to use current limiting electrical reactors to limit the flow of electrical current in a circuit under short circuit conditions, or under other operating conditions that draw large amounts of current.
One such application of a current limiting reactor, for example, is in the power supply used to regulate and control current supplied to an arc type furnace. In this application the power supply is a direct current power supply, such as a rectifier. The furnace has an electrode which contacts the furnace charge, metal for example, and melts the charge. In this application the electrode creates a short circuit condition when it contacts the charge which quickly raises the current drawn by the electrode. To limit current drawn, the current limiting reactor is placed in circuit between the furnace and the power supply. This placement of the reactor introduces reactance to the circuit which limits the rate of rise of current flowing to the electrode under short circuit conditions thereby allowing the power supply sufficient time to decrease the current flow to the electrode.
While the use of such reactors in power supplies for furnaces is known, the design of these reactors has been cumbersome and expensive. The state of the art reactor comprises a water cooled copper conductor of circular cross-section wound in a helical spiral. This reactor has a three-dimensional space requirement governed by the radius of the winding and the axial length of the winding. In practise these reactors may be as much as 4 feet in diameter and have an axial length of 4 feet or more. As a result of the winding configuration, floor space adjacent the power supply, or remotely in a separate room, is required for the reactor.